Error(0x85):GATT ERROR

[hucs]

Hi,I have trouble when I try my nRF51822 board with example program of hrs. I use nRF Master Control in my phone to connect with my board.scanning is ok.But when it try to connect, sometimes it can connected with my board, but soon disconnected because of Error(0x85):GATT ERROR. Sometimes this error happened when discovering services. What does it mean? My hardware is based on nRF51822QFAAG2.

[Hung Bui]

@furnaceX: Next time please add your question in the comment section or create a new question. We found that this could be Android's issue. Could you try, on the phone, to go to Setting -> Application -> Application manager -> All app -> look for Bluetooth and click Force Close and Clear Data ? And test again.

[furnaceX]

I didn't find a specific "bluetooth" only app. Just things like "Bluetooth MIDI Service", "bluetooth share", etc. Anyway, I forced close and cleared data on all of them. Didn't fix it.

I have 3 identical devices... On the samsung S7, one I can connect to all of the time, one some of the time, and the 3rd, I can connect to if I push the button on it, it will connect for a short time ~15 seconds (otherwise it fails to connect immediately, as I showed above). On a Moto X (Android 5.1) all 3 devices connect without anything special (i.e. no button clicks) and stay connect.

[Fanis]

It seems that playing with connection intervals and connection interval update times can solve the problem. I have had an issue in which i could connect with honor 9 to the main firmware and couldn't to dfu bootloader. Increasing conn parameter update delays seems to solve this problem (by default there was a 100ms after first connection and honor reports disconnect right after connect, or sometimes 0x85 error)